U.S. Pat. No. 4,062,732 issued Dec. 13, 1977 to Lehmann et al discloses a process for producing an acid stable protease with a broad activity spectrum by culturing a fungus strain of the species Rhizopus rhizopodiformis isolated from earth samples. The fungus strain has the depository number CBS 227.75 and is deposited in the Centraal Bureau voor Schimmel-Cultures in Baarn (the Netherlands).